Following one man's task of building a virtual world from the comfort of his pajamas. Discusses Procedural Terrain, Vegetation and Architecture generation. Also OpenCL, Voxels and Computer Graphics in general.

Sunday, May 31, 2015

This post is mostly about how I feel about procedural generation and where we will be going next.

A couple of months ago we released Voxel Farm and Voxel Studio. Many of you have already played with it and often we get the same questions: why so much focus on artist input, what happened to building entire worlds with the click of a button?

The short answer is "classic" real time procedural generation is bad and should be avoided, but if you stop reading here you will get the wrong idea, so I really encourage you to get to my final point.

While you can customize our engine to produce any procedural object you may think of, our current out-of the-box components favor artist generated content. This is how our current workflow looks like:

It can be read like this: The world is the result of multiple user-supplied data layers which are shuffled together. Variety is introduced at the mixer level, so there is a significant procedural aspect to this, but at the same time the final output is limited to combinations of the samples provided by a human as input files.

This approach is fast enough to allow real time generation, and at the same time it can produce interesting and varied enough results to keep humans interested for a while. The output can be incredibly good, in fact as good as the talent of the human who created the input files. But here is also the problem. You still need to provide reasonably good input to the system.

This is the first piece of bad news. Procedural generation is not a replacement for talent. If you lack artistic talent, procedural generation is not likely to help much. You can amplify an initial set into a much larger set, but you can't turn a bad set into a good one. A microphone won't make you a good singer.

The second batch of bad news is the one you should worry about: Procedural generation has a cost. I have posted about this before. You cannot make something out of nothing. Entropy matters. It takes serious effort for a team of human creators to come up with interesting scenes. In the same way, you must pay a similar price (in energy or time) when you synthesize something from scratch. As a rule of thumb, the complexity of the system you can generate is proportional to the amount of energy you spend. If you think you can generate entire planets on-the-fly on a console or PC, you are up for some serious disappointment.

I will be very specific about this. Procedural content based on local mathematical functions like Perlin, Voronoi, etc. cannot hold our interest and it is guaranteed to produce boring content. Procedural content based on simulation and AI can rival human nature and what humans create, but it is not fast enough for real time generation.

Is there any point in pursuing real time procedural generation? Absolutely, but you have to take it for what it is. As I see it, the only available path at this point is to have large sets of interesting content that can be used to produce even larger sets, but there are limits for how much you can grow the content before it becomes predictable.

For real time generation, our goal will be to help people produce better base content sets. These could be produced on-the-fly, assuming the application allows some time and energy for it.

Here is where we are going next:

Hopefully that explains why we chose to start with a system that can closely obey the instructions of an artist. Our goal is to replace human work by automating the artist, not by automating the subject. We have not taken a detour, I believe this is the only way.

Wednesday, May 13, 2015

We are often asked if Voxel Farm can do a cartoony look. As a side project I decided to give it a try. This is what I managed to do in a couple of nights:

I had been recently exposed to Adventure Time by my kids, the influences are clear. This programmer's art so go easy on me. Also there is very little detail. All materials are solid colors. Only two instanced objects (a tree and a stump) but I think it works for the most part.

You can read a guide on how this was built here. It served as an example of how to create a biome from scratch in Voxel Studio. We will probably expand this project to cover other topics like voxel instances and runtime extensions.